Combined MR-PET systems or CT-PET systems are known in which it is possible to record both MR or CT measurement data and emission tomography measurement data in the same hybrid system. The first imaging modality (MR or CT) is able to depict the examination volume to be displayed in a first image, which mainly shows the anatomical relationships in the object to be examined. The second imaging modality (in this case PET) can be used to generate a further image. This mainly shows the distribution of a radioactive substance in the body and is hence able to depict biochemical and physiological functions (functional imaging).
The parallel creation of an image with two different modalities enables an improved evaluation of the state of the object to be examined.
During an examination, the object to be examined or the patient are often moved to different table positions to enable different regions of the patient to be depicted. With PET-CT imaging, a recording schedule is known with which the PET measurement data is recorded successively at different table positions with a predetermined recording time for each table position (so-called “step and shoot” mode). The CT measurement data are then recorded either before or after the performance of the PET measurement data recording.